Pipe fitting

ABSTRACT

A pipe joint for connecting abutting ends of cast iron pipes comprising in a flexible sleeve, such as of rubber which is surrounded by one split socket, under stress, in particular out of cast iron, or a material that corresponds with its elasticity and has a resistance against corrosion that is comparable with that of the pipes to be connected.

United States Patent [191 Bakkerus 51 Feb. 27, 1973 [54] PIPE FITTING[75] Inventor: Hermanus Netherlands [22] Filed: Aug. 16, 1971 [21] Appl.No.: 171,845

Bakkerus, Voorburg,

[30] Foreign Application Priority Data Aug. 20, 1970 Netherlands"7012379 [52] US. Cl .185/236, 285/373 [51] Int. Cl ..Fl6l 21/06 [58]Field of Search ..285/236, 373, 419, DIG. 22; 24/20, 257, 259 C, 381

[5 6] References Cited UNITED STATES PATENTS 2,451,438 10/1948 Hartman..285/236 3,353,567 1l/l967 Isreeli ...24/257 R X 3,439,945 4/1969Chambers et al ..285/373 3 ,402,946 9/1968 Dedian ..285/236 3,249,6855/1966 I-Ieflin ..285/236 X 3,334,928 8/1967 Schmunk... .....285/236 X3,464,721 9/1969 Surko ..285/236 X FOREIGN PATENTS OR APPLICATIONS1,142,077 3/1957 France ..285/425 1,282,373 11/1968 Germany ..285/373497,239 11/1950 Belgium ..285/236 Primary ExaminerThomas F. CallaghanAttorney-Hugh Adam Kirk [57] ABSTRACT A pipe joint for connectingabutting ends of cast iron pipes comprising in a flexible sleeve, suchas of rubber which is surrounded by one split socket, under stress, inparticular out of cast iron, or a material that corresponds with itselasticity and has a resistance against corrosion that is comparablewith that of the pipes to be connected.

3 Claims, 1 Drawing Figure PATENTEDFEBZYIBYS 3.718351 HERMAuua BA nKERU:

ATTORNEY PIPE FITTING Background of the Invention The invention relatesto a pipe fitting, in particular for connecting cast iron pipes that,without being premachined are connected to each other coaxially, and inwhich a certain flexibility and an adaptation to the diameters of thevarious pipes is guaranteed automatically.

It is known in the art to connect a cast iron pipe with a normal end toa socket end of the following pipe, and filling the socket end with aseal, such as joint filler, that is held in place with a cast-in leadring, which is then driven in with the aid of a handtool. Thisconnection has been the customary one for years, especially when thepipe line is used for liquids or gases containing liquid. Ontransporting dry gases, however, the joint filler has the tendency todry up, as a result of which there is a great chance of leakageespecially when small saggings or deformations of the pipe line occur.

Consequently the modern trend is a pipe connection without a socket endand without the drawbacks involved, or the achievement of the connectioninvolving expensive labor costs.

SUMMARY OF THE INVENTION It is the object of the invention to improvethis, maintain an absolutely closed fitting that is of simplemanufacture and is able to compensate easily for the differences indiameter of the pipes within the tolerances, and moreover is insensitiveto small deviations from the center lines of the pipes thereby beingunafiected by differences in sagging of the various pipes.

Therefore, according to the invention, the fitting surrounds theabutting ends of the pipes and comprises one rubber sleeve surrounded byone split socket, under stress, and made out of cast iron or a materialthat corresponds with it or the pipe as regard to elasticity andresistance against corrosion. Preferably the split socket is made of thesame cast iron as the pipes, but out of a pipe with a larger nominaldiameter. These sockets may, for instance, then be made from theflawless parts of pipes that for one reason or other are condemned.Moreover, cast iron has the advantage, that within Hookes Law, itpermits a greater elastic deformation than steel.

BRIEF DESCRIPTION OF THE DRAWING The invention is further elucidatedbelow with reference to the accompanying drawing of a side view of anembodiment of a pipe fitting according to the invention on abuttingsections of pipe, with part thereof being shown in cross-section.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT According to the drawing,one end of a pipe 1 and one end of a pipe 2 are butted against eachother. Around their abutting ends 3, a flexible rubber sleeve 4 is slidpreferably somewhat snugly. Around the sleeve 4 is a clamping socket 5which derives its elastic action from the facts that it is split at 6and that the internal diameter of this socket 5 is smaller than theexternal diameter of the unclamped rubber sleeve 4. Owing to thepresence of a gap 6 at the split in the socket 5,

sleeve 4 effectively clamps around the pipe ends, and an elastic fittingbetween the two pipes l and 2 is obtained.

The fitting is brought about by placing sleeve 4 around one end of pipe1 and placing over it socket 5 of which gap 6 is forced open with theaid of a spacer or an expanding tool, so that socket 5 is free fromsleeve 4 and does not exert a compressive force on it. Then the end ofpipe 2 is inserted in sleeve 4, which involves little effort because thesleeve is flexible and no compressive force is exerted on it by socket5. As soon as the end of pipes 1 and 2 are butted against each other,the spacer or the expanding tool is removed from the split 6 of socket5, as a result of which the split or gap 6 becomes much narrower. Owingto the stress that there is now applied by the resiliency of the socket5, sleeve 4 compressed around the ends of the pipes l and 2, and acomplete sealing of their abutting ends 3 is effected. Even when fairlyhigh pressure prevails in the duct or pipes l and 2, no leakage willoccur because the flexible sleeve 4 is substantially completelysurrounded by elastically stretched socket 5, and bulging of the sleeve4 could only be possible at the point of of intersection of the abuttingend and the split or gap 6. Actually, gap 6 has such a slight breadththat a possibility of leakage on this point need not be feared.

With respect to the material or composition of the socket 5, it can beof cast iron which is known to have a good corrosion--resistance, or thesocket 5 can be made of a similar resisilent material which is alsocorrosion-resistant. The socket 5 preferably made of the same materialas the pipes l and 2, such as being cut off from pipe with a largernominal diameter. Gap 6 therein can be milled or sawn or ground in thepipe of which socket 5 is made. Though in the embodiment shown, gap 6 isparallel to the pipes 1 and 2, it may be advantageous to make it runslantingly with respect to these pipes, to make it run sawtooth-wise, ifdesired. The breadth of gap 6, however, must in all cases be sosufficient to compress the flexible sleeve 4 and clamp it around thepipe ends 3.

The rubber sleeve 4 can be chosen to be resistant to many kinds ofmedia. It can be either a natural rubber or a synthetic rubber or aplastic that meets the requirements for a long-term corrosion-resistanceand also remains flexible and does not age into a non-flexible mass.Generally, the thickness of the sleeve 4 is chosen so that it easilytakes up any differences in diameter of the two pipes l and 2 within thetolerances of these pipes. Although the drawing shows the sleeve 4protruding beyond the ends of the socket 5, it is also possible that ashorter sleeve 4 can be used so that it lies entirely within the socket5.

Because sleeve 4 forms a flexible intermediary between pipe ends 3 andsocket 5, there is a certain degree of play present so that the centerlines of the pipes 1 and 2 may make a small angle with each other. Thismeans that a pipeline laid in the soil with the fittings of thisinvention will compensate easily for the differences in sagging betweenthe various pipes of the line.

Although cast iron is described for the pipes 1 and 2 and socket 5,other materials can be used in a similar way, provided pipes of othermaterial cannot be effected in a similar way provided the split socket 5has sufficient elasticity to clamp the flexible sleeve 4 tight aroundthe pipe ends 3. The most important requirement the material of socket 5has to meet is that on forcing open and widening gap 6, socket 5 is notloaded beyond its elasticity limit, which would cause its plasticdeformation, and then on removing the tool that keeps gap 6 open, thesleeve 4 would not be compressed sufficiently.

I claim:

1. A pipe fitting for connecting the abutting ends of pipes, consistingof an elastic circumferentially continuous sealing sleeve surroundingsaid ends, and an inherently resilient corrosion resistant split socketunder stress comprising a cast-iron cylindrical tube having internal andexternal concentric surfaces throughout their entire lengths free of anyinternal and external projections, and the gap of said split extends thefull length of said socket and is relatively narrow, the normalunstressed internal diameter of said socket being less than the normaluncompressed external diameter of said sleeve, and said socket beinggenerally equal in length to said sleeve and surrounding andcompressing, by its own resiliency only, said sleeve from both sides ofand including said abutting ends of said pipes.

2. A pipe fitting according to claim 1 wherein the split in the socketis parallel to the axis of said socket.

3. A pipe fitting according to claim 1 wherein said sleeve is rubber.

1. A pipe fitting foR connecting the abutting ends of pipes, consistingof an elastic circumferentially continuous sealing sleeve surroundingsaid ends, and an inherently resilient corrosion resistant split socketunder stress comprising a castiron cylindrical tube having internal andexternal concentric surfaces throughout their entire lengths free of anyinternal and external projections, and the gap of said split extends thefull length of said socket and is relatively narrow, the normalunstressed internal diameter of said socket being less than the normaluncompressed external diameter of said sleeve, and said socket beinggenerally equal in length to said sleeve and surrounding andcompressing, by its own resiliency only, said sleeve from both sides ofand including said abutting ends of said pipes.
 2. A pipe fittingaccording to claim 1 wherein the split in the socket is parallel to theaxis of said socket.
 3. A pipe fitting according to claim 1 wherein saidsleeve is rubber.